Twist agitation - has anyone ever done tests?

[Arvee]

I know this subject has been discussed about a million times before, but I'd like to get to the root of it.

Has anyone ever run actual tests to verify that twiddle stick agitation causes uneven development or is inferior to the inversion method? I've read a fairly large number of threads discussing this issue and virtually all the responses seem to be absolutely sure that the spinner is inferior and causes problems; I suspect that the statements are simply parroting what that individual has heard or read elsewhere, not the results of a formal analysis. Statements vary from end to end density differences and/or edge to edge density differences or generally an overall poorer method of agitation. To me, spinning is Jobo rotation in the horizontal axis without the film exiting the developer into air space.

What I'm getting at here is the proposition that spinner agitation causes uneven development seems more likely to be 'photo mythology' that has been propagated over the years and has taken on the aura of being 'gospel truth,' it appears to not be the result of a formal in depth side by side test.

What I'd like to ask is do any of you know of a formal experiment that has been performed to determine if there really are dramatic differences between spinner and inversion methods of agitation. And I'm also asking if such an experiment has been conducted, has it been performed to the level and extent of the in depth experiments performed by the late Richard J. Henry in his last book 'Photographic Controls...?'

If anyone knows of direct evidence of such experiments, could you please provide links to the information? No hearsay, please. I'm asking because I am sick and tired of reading that it is indeed fact without any factual evidence or proof to back the assertion.

PS I am completely aware of the Ilford recommendation only using the spinner for the initial cycle of agitation but provides no additional information why you shouldn't continue with the spinner for the duration of the development cycle.

Perhaps Mr. Benskin knows of the real truth; it's sad that PE is no longer with us to proffer advice. He is missed! Matt King, do you know of actual evidence of any differences?

 

[Eric Rose]

I do both and see no difference with 35mm films. The key is to not twiddle to fast.

 

[JerseyDoug]

I'm pretty sure it's Paterson, not Ilford, that recommends using the agitator only at the beginning of the process. It never occurred to me to risk a roll of film by ignoring what sounds like very reasonable advice.

 

[faberryman]

If anyone knows of direct evidence of such experiments, could you please provide links to the information? No hearsay, please. I'm asking because I am sick and tired of reading that it is indeed fact without any factual evidence or proof to back the assertion.

Here are the agitation instructions.

Agitation

After pouring in the first solution, immediately insert the agitator and twist sharply back and forth three or four times, then lightly tap the bottom of the tank on the bench to dislodge any air bubbles which might form on the surface of the film. Now push the cap on and make sure that it fits all the way round.

At the end of the first minute and of each subsequent minute, invert the tank, at once returning it to the upright position, and tap the tank on the bench as before.

This level of agitation is correct for the majority of films and developers. Some developer instructions, particularly colour developers, may specify a different amount of agitation. If so, follow those instructions but otherwise adhere to these recommendations. Consistency is important for repeatable good results.

Do you use Patterson tanks? Do you twiddle? What has been your personal experience?

 

[BradS]

Sometimes, I twiddle vigorously and sometimes do the wobbly figure eight according to my whim.
It makes no significant difference to my eye.
Patterson System IV tanks and reels....for the last few decades.

 

[RalphLambrecht]

I know this subject has been discussed about a million times before, but I'd like to get to the root of it.

Has anyone ever run actual tests to verify that twiddle stick agitation causes uneven development or is inferior to the inversion method? I've read a fairly large number of threads discussing this issue and virtually all the responses seem to be absolutely sure that the spinner is inferior and causes problems; I suspect that the statements are simply parroting what that individual has heard or read elsewhere, not the results of a formal analysis. Statements vary from end to end density differences and/or edge to edge density differences or generally an overall poorer method of agitation. To me, spinning is Jobo rotation in the horizontal axis without the film exiting the developer into air space.

What I'm getting at here is the proposition that spinner agitation causes uneven development seems more likely to be 'photo mythology' that has been propagated over the years and has taken on the aura of being 'gospel truth,' it appears to not be the result of a formal in depth side by side test.

What I'd like to ask is do any of you know of a formal experiment that has been performed to determine if there really are dramatic differences between spinner and inversion methods of agitation. And I'm also asking if such an experiment has been conducted, has it been performed to the level and extent of the in depth experiments performed by the late Richard J. Henry in his last book 'Photographic Controls...?'

If anyone knows of direct evidence of such experiments, could you please provide links to the information? No hearsay, please. I'm asking because I am sick and tired of reading that it is indeed fact without any factual evidence or proof to back the assertion.

PS I am completely aware of the Ilford recommendation only using the spinner for the initial cycle of agitation but provides no additional information why you shouldn't continue with the spinner for the duration of the development cycle.

Perhaps Mr. Benskin knows of the real truth; it's sad that PE is no longer with us to proffer advice. He is missed! Matt King, do you know of actual evidence of any differences?

The most even development I ever got was from constant rotation in the Jobo.

 

[Paul Howell]

In the 60s while in high school we had Kodak tanks with aprons and GAF/Ansco tanks with twiddle sticks. The ANSCO tanks we used had no caps, it was either slosh the tanks by tipping from side to side or use the agitator stick that rotated the reel. We used replenished D76, to my memory I did notice any difference between the 2. I currently use SS, Patterson, and Unicolor film tanks with a motor base, and large tanks with hangers for 4X5. I subtract 20% from my personal development times or a given time when using the Unicolor tank, all seem to do a good job, even development across the negatives.

 

[pentaxuser]

I wish you luck in getting actual sources of scientific evidence. Already all of the posters are giving you their experience of what has worked for them. This is all most of us can do.

If we were to respond strictly to what you have asked the answers would be short to the point of sounding abrupt

If you wish us to stick strictly to the terms of your request then it might help if you were to re-iterate exactly what your terms are

If you do, then expect short or no answers but if you do not wish the thread to end this way then fine, most of us will continue to respond in our usual way

pentaxuser

 

[MattKing]

I'm prepared to rely on the written Paterson instructions - first 30 seconds only for the agitation sticks.
I don't know how you would construct a reliable experiment, given the variety of tanks, reels, developers, films, temperatures and "twizzlers".
The only time I used that form of agitation consistently was when I was a teenager and, for a brief period, used a GAF/Ansco tank that did not permit inversion.
I have used "figure 8" agitation successfully with Kodak Apron tanks.
I always advise people that agitation should be such that the liquid tumbles through the reel and film. You cannot accomplish that with the agitation sticks.
And by the way, I've edited your thread title so that people have at least a hint about what one might find in the thread.

 

[MattKing]

Perhaps Mr. Benskin knows of the real truth; it's sad that PE is no longer with us to proffer advice. He is missed! Matt King, do you know of actual evidence of any differences?

I find myself humbled by inclusion in this trio.

I expect most of the careful formal analysis has been done in order to ensure even development in commercial lab environments. And I can't think of any commercial development equipment that comes even close to providing the environment in a stationary vertical small tank with a reel rotating in it.

 

[Sirius Glass]

The most even development I ever got was from constant rotation in the Jobo.

Exactly the reason that I use the Jobo processor for all my development needs from subminiatures to 4"x5".

 

[Arvee]

As I expected-observation without instrumentation. I am now beginning to think that 'eyeball' calibration might just be good enough, given the grand scheme of things. I've been bouncing back and forth between the two methods for years and I have yet to see anything like the naysayers articulate. Think my original judgement feels pretty good-most likely mythology-unless someone comes up with info saying otherwise.

My skies have been pretty uniform with either method so I'll continue to alternate since I see no evidence in 8X prints.

And, when I don't want developer stains on my hands, I'll pick up the Paterson or the ancient Yankee or GAF tank.

Thanks, guys, for all your comments.

I will add one thing though, Kodak's 5X at 30 sec intervals with SS tends to give me blown highlights in my prints vs the Ilford recommendation 4X in 60 sec in SS tanks. I think Kodak's scheme is a bit too vigorous. Four diddles with the swizzle stick every 60 sec gives me creamy vs blinding highlights. I learned photography with graded paper, Kodak/Agfa, and hate having to dial in a print with the VC stuff. Prints on graded paper just look better but, alas, where can one find the good stuff like Agfa's Brovira 111 these days. (Ilford D100/D76 stock for every format, occasionally a smidge of HP5).

Thanks, again, everyone!

 

[Arvee]

I find myself humbled by inclusion in this trio.

I expect most of the careful formal analysis has been done in order to ensure even development in commercial lab environments. And I can't think of any commercial development equipment that comes even close to providing the environment in a stationary vertical small tank with a reel rotating in it.

Btw, Matt, thanks for adjusting the title...

 

[MattKing]

I don't think it is mythology.
I think its aversion to problems.
From the perspective of those who used to see lots and lots of people trying lots of things.
People like Paterson themselves - mostly as a result of information from retailers.
There used to be an entire universe of information gathering out there - people who would buy stuff from stores, have either success or failure, and then get help from the people who worked in those stores.
Who would then share what they had learned from their experience and their customer's experience. Shared both with the customers, and the suppliers.
That was actually a very effective means of improving the products and techniques.

 

[Sirius Glass]

I have used a stick to turn reels, turned tanks over, moved a tank in a circle or figure eight and as long as I followed the tank manufacture's instruction I never had a development problem. Of course the 4"x5" Yankee tank did throw out chemicals when I agitated as instructed, so I brought the tank back to FreeStyle to exchange for the Jobo 3010 Expert Drum, but the film did develop properly.

 

[Arvee]

I find myself humbled by inclusion in this trio.

I expect most of the careful formal analysis has been done in order to ensure even development in commercial lab environments. And I can't think of any commercial development equipment that comes even close to providing the environment in a stationary vertical small tank with a reel rotating in it.

I seem to recall you have somewhat of a background with TGYF.....

 

[MattKing]

I seem to recall you have somewhat of a background with TGYF.....

Never as an employee, and never in the sort of scientific or technical capacity that the other two evidence.

 

[Huss]

And, when I don't want developer stains on my hands, I'll pick up the Paterson or the ancient Yankee or GAF tank.

I put on nitrile 'examination' gloves when I develop film.

 

[AgX]

As a side question, which manufacturers offer twist-agitation tanks today?

Jobo abandoned such in 1970.

 

[brbo]

Paterson.

 

[npl]

Twiddle stick agitation seem more common when developing color films, due to the short times and warm water bath.. maybe you'll get more lucky in dedicated forum / sub-forums ?

It would be interesting to see a publication on that subjet, if you ever find one. Good luck

 

[Helge]

My internal mental model of this problem is that you are moving a thin long spiral "slice" of liquid that due to laminar forces clings to the film. With more turbulence and replacement at the edges of the spiral.
When you twiddle or rotate, the spiral gets moved all the length of the film, with the output portion getting more exhausted between twiddle rounds than the intake.
And that is indeed one of the problems I've observed when only twiddling. IE uneven development from one end to the other.
Whether that is confirmation bias or not I'm not sure.
I think for twiddling to work, you'd have to do it continuously in one direction. And that gets very hard on the fingers.
I've contemplated trying to use a motor on the stick for the fixing stage. And just let it rip for ten minutes.
But for development, why not use the most efficient way of getting fresh developer on the film?
There is a reason reversible tanks was a big deal when they arrived.

For stand development twiddle seems to be good though. Exactly what the doctor prescribed. Avoids bromide drag and moves the developer slightly from one portion of the film to another. Without getting completely fresh developer to film.

 

[Arvee]

Several years ago I came across a post in a thread on agitation by Prof. H. Lynn Jones who I believe was the chair of the Photography Dept. at Austin CC in TX. He did extensive testing of the various methods of agitation and concluded that there were only minor variations in density between the two methods while adding that the Dobro Method (an instructor at Brooks) proved to be the method providing the most uniform densities of any spiral tank method. I recall that it was a formal in depth study that was conducted with necessary instrumentation. He described the Dobro method as twisting action with an inversion that he was unable to visually put into words. This is the only formal testing that I have ever encountered. I was hoping someone on the forum might have found others.
I can't find the actual post discussing the actual test measurements but I did find a paper he wrote that references the tests. I believe that the Professor passed away sometime in the last year or two.

Here is the link to his paper: https://www.mr-alvandi.com/downloads/film-and-processing/black-and-white-developing-films.pdf
(pp. 10)

 

[gone]

There's a large body of evidence on these swizzle sticks regarding surge marks. Mine is experiential. The one and only time I tried it I got surge marks, and took that little stick and pitched it as far as I could throw it. Haven't had that occur again in the last 20-25 years. It's not hard to connect the dots.

 

[BCM]

I did tests years ago between several development methods when we were testing and starting to manufacture the BTZS Film Tubes. There is high variability in person-to-person testing. The best method for testing is to expose a roll/sheet to middle gray (a smooth sheet of evenly lit poster board verified with a light meter) and then read the developed film with a densitometer.